EN vs UL current ratings

[JohnW2]

Hi folks,

Recentky looking at the ratings of Wago connectors, I was reminded how different the EN and UL current ratings of items can be. For example, with 221-61x Wagos (for conductors up to 6mm²), the EN rating (which is the one we would look at) is 41 A, whereas the UL one is only 30 A.

I wonder whether the UL figures are 'over-cautious', the EN ones 'not cautious enough', or what?

 

[plugwash]

A few things I observe.

1. The EN ratings seem to be "odd" numbers, while the UL ratings are standard american circuit ratings.
2. The americans seem to be a bit more cautious on default wire sizes for a given current than we do.
3. The largest american conductor size the connectors support is 10AWG which is a fair bit smaller than 6mm²

IIRC the next american breaker size over 30A is 40A, which would normally require 8AWG wire, which is too big for the wago.

 

[JohnW2]

A few things I observe.

1. The EN ratings seem to be "odd" numbers, while the UL ratings are standard american circuit ratings.
2. The americans seem to be a bit more cautious on default wire sizes for a given current than we do.
3. The largest american conductor size the connectors support is 10AWG which is a fair bit smaller than 6mm²

IIRC the next american breaker size over 30A is 40A, which would normally require 8AWG wire, which is too big for the wago.

As for your (1), I suspect the 41 A may relate to the fact that 6mm might be on a 40A OPD?
I agree about the rest.

 

[mattylad]

Have you got a list of both these ratings please?

 

[JohnW2]

Have you got a list of both these ratings please?

I'm not sure what you want a list' of ...

For all 221-61x connectors (conductors to 6mm²), EN rating is 41 A and UL rating is 30 A
For all 221-41x connectors (conductors to 4mm²) the EN rating is 32 A and the UL one 20 A

Is there anything else you would like'listed'?

It rather sounds as if the Americans have gone fore 'round numbers', which suggests that they may well not relate to the actual 'maximum safe current' as determined by testing? On the other hand, it seems more than a coincidence that the EN "32 A" corersponds to a very common rating of MCB/RCBO and circuit - so, again, perhaps not actually the 'maximum' as determined by testing?

 

[mattylad]

My apologies, I was thinking wire size, not wago's

 

[JohnW2]

My apologies, I was thinking wire size, not wago's

Oh, sorry.

We know the EN figures for metric cables, and Mr Google knows all about the UL figures for AWG cables (e.g. see below), but I doubt there is ay direct source of the converse (UL figure for metric or EN ones for AWG). There are no particularly close sizes of metric and AWG cables, but the (UL) ratings for AWG cables are clearly quite a lot lower than EN ratings for metric ones - e.g. per below table, even AWG 12 (3.32mm) cable only has a rating of 20A, as compared with 27 A (Method C) for 2.5mm²

 

[mattylad]

Thanks John, a classic case of not reading the posts properly
Unfortunatly these tables rarely have our actual wire size on, usually the AWG equivelent so we have to guestimate.

 

[JohnW2]

Thanks John, a classic case of not reading the posts properly

We're all guilty of that quite often

Unfortunatly these tables rarely have our actual wire size on, usually the AWG equivelent so we have to guestimate.

As I implied, there's not really any reason for figures to be presented in the figures in that fashion, since very few people would be interested in UL ratings for metric cables or EN ratings for AWG ones.

 

[mattylad]

I would, I sometimnes have to build panels that are for UL countries, kind of to UL spec but not
I only use metric cables as that's all we can (read "want to") get.